class HungrySingleton {
  private static instance: HungrySingleton = new HungrySingleton()

  private constructor() { }

  static getInstance() {
    console.log('HungrySingleton.instance :>> ', HungrySingleton.instance);
    return HungrySingleton.instance
  }
}

const install3 = HungrySingleton.getInstance()
const install4 = HungrySingleton.getInstance()
console.log(install3 === install4)